2 research outputs found
Switchable Bioelectrocatalysis Controlled by Dual Stimuli-Responsive Polymeric Interface
The engineering of bionanointerfaces
using stimuli-responsive polymers offers a new dimension in the design
of novel bioelectronic interfaces. The integration of electrode surfaces
with stimuli-responsive molecular cues provides a direct control and
ability to switch and tune physical and chemical properties of bioelectronic
interfaces in various biodevices. Here, we report a dual-responsive
biointerface employing a positively responding dual-switchable polymer,
polyÂ(NIPAAm-<i>co</i>-DEAEMA)-<i>b-</i>HEAAm,
to control and regulate enzyme-based bioelectrocatalysis. The design
interface exhibits reversible activation–deactivation of bioelectrocatalytic
reactions in response to change in temperature and in pH, which allows
manipulation of biomolecular interactions to produce on/off switchable
conditions. Using electrochemical measurements, we demonstrate that
interfacial bioelectrochemical properties can be tuned over a modest
range of temperature (i.e., 20–60 °C) and pH (i.e., pH
4–8) of the medium. The resulting dual-switchable interface
may have important implications not only for the design of responsive
biocatalysis and on-demand operation of biosensors, but also as an
aid to elucidating electron-transport pathways and mechanisms in living
organisms by mimicking the dynamic properties of complex biological
environments and processes
Studies on Bacterial Proteins Corona Interaction with Saponin Imprinted ZnO Nanohoneycombs and Their Toxic Responses
Molecular
imprinting generates robust, efficient, and highly mesoporous
surfaces for biointeractions. Mechanistic interfacial interaction
between the surface of core substrate and protein corona is crucial
to understand the substantial microbial toxic responses at a nanoscale.
In this study, we have focused on the mechanistic interactions between
synthesized saponin imprinted zinc oxide nanohoneycombs (SIZnO NHs),
average size 80–125 nm, surface area 20.27 m<sup>2</sup>/g,
average pore density 0.23 pore/nm and number-average pore size 3.74
nm and proteins corona of bacteria. The produced SIZnO NHs as potential
antifungal and antibacterial agents have been studied on <i>Sclerotium
rolfsii (S. rolfsii)</i>, <i>Pythium debarynum (P. debarynum)
and Escherichia coli (E. coli)</i>, <i>Staphylococcus aureus
(S. aureus)</i>, respectively. SIZnO NHs exhibited the highest
antibacterial (∼50%) and antifungal (∼40%) activity
against Gram-negative bacteria (<i>E. coli</i>) and fungus
(<i>P. debarynum)</i>, respectively at concentration of
0.1 mol. Scanning electron spectroscopy (SEM) observation showed that
the ZnO NHs ruptured the cell wall of bacteria and internalized into
the cell. The molecular docking studies were carried out using binding
proteins present in the gram negative bacteria (<i>lipopolysaccharide</i> and <i>lipocalin Blc</i>) and gram positive bacteria (Staphylococcal
Protein A, SpA). It was envisaged that the proteins present in the
bacterial cell wall were found to interact and adsorb on the surface
of SIZnO NHs thereby blocking the active sites of the proteins used
for cell wall synthesis. The binding affinity and interaction energies
were higher in the case of binding proteins present in gram negative
bacteria as compared to that of gram positive bacteria. In addition,
a kinetic mathematical model (KMM) was developed in MATLAB to predict
the internalization in the bacterial cellular uptake of the ZnO NHs
for better understanding of their controlled toxicity. The results
obtained from KMM exhibited a good agreement with the experimental
data. Exploration of mechanistic interactions, as well as the formation
of bioconjugate of proteins and ZnO NHs would play a key role to interpret
more complex biological systems in nature